Audio problem: When Zane is coming in on the chopper, another soldier gives him a bottle and says, "Take a swig." The guys lips are still moving even though he's already said the line. (00:19:30)
Continuity mistake: After the bad guys shoots the pilot, blood squirts onto the window. However the next shot shows the chopper heading down (with the dead pilot) but there is no blood on the window. (00:19:55)
Continuity mistake: When the pilot is shot, blood shoots onto the window in the upper right part of the screen (where the glass and the metal meet). Later, the blood is squarely in the middle of the window. (00:19:55)
Continuity mistake: When Zane is coming in by chopper, the soldier gets shot up and Zane takes out his weapon to shoot. The blood on his finger changes from the wide shot of him and the weapon and the close-up shot of his finger on the trigger. (00:20:50)
Continuity mistake: When Zane walks into the cantina and asks for a game of pool, the guy has just broke the rack with most of the balls staying where they were. The next shot shows all the balls being closer to the side rail than they were. (00:22:05)
Continuity mistake: When Berenger takes Zane into his room, he puts his keys down on a crate. In the shot just prior to that there's a book where the keys are laid. (00:24:25)
Continuity mistake: The site where Berenger put the marker down by the river and the site where the mercenary picked up the marker don't look the same (different rock pile, different tree, different barbed wire configuration, etc.). (00:56:35 - 00:57:55)
Continuity mistake: After the fight with Zane about ending the mission, Berenger puts a marker down on the ground. Later the mercenary sniper picks up the marker, but it's a different marker than Berenger put down. (00:56:45 - 00:58:05)
Other mistake: Berenger probably took a toe or two off when he stabbed the guys foot, but he moved around just fine afterwards. (01:13:40)
Continuity mistake: When Zane enters the ruins after going crazy he fires three bullets at his shadow and hit the wall. After he falls to the ground laughing the camera pans out and there are no more bullet holes where he shot at the wall. (01:21:05)
Continuity mistake: When the Surgeon is torturing Beckett, Beckett's arms are about shoulder width apart tied to the bamboo. A couple scenes later, his arms are tied further apart. This makes it really odd because the Surgeon was cutting his finger, which is about a foot away from where he stands up. (01:28:25 - 01:29:35)
Continuity mistake: When they're in the jungle in Panama they see a train go past which has the Queensland rail (in Australia) sign on it.
Factual error: In the opening sequence, the range for the shot is confirmed as 650 yards. Moments before the shot, AFTER he had his target centered in his scope, Berenger swings the muzzle of the rifle at least 10 degrees. At 650 yards a change of only a single degree in the angle of the muzzle to the target would mean that the target would have to move 11.34 yards laterally in order for the shot to hit. If Berenger actually had to swing his rifle ten degrees in the span of a second in order to keep his target in view, that would mean the target was sprinting at a speed of 340.32 feet per second, or about 232 miles per hour, and had covered 113.44 yards during that time. Absolutely impossible.
Continuity mistake: In the beginning, when Tom Berenger and his spotter are trying to get on the chopper, the spotter gets shot. First, they show blood on his face. In the next scene it is clean and in the scene after that is it bloody again. The appearance of his wound changes too.
Continuity mistake: When Miller shoots El Cirujano, who was torturing Beckett, it's a rainy night. In the side shot of Miller's fired bullet, in the background there is a definitely daytime forest, then in the next shot, it's night again.
Continuity mistake: When Billy Zane slides down into the river, the overhead shot shows him (or a stunt double) completely go into the river. But the next shot, Billy Zane magically keeps his rifle and his upper body dry and above the water line.
Continuity mistake: When Berenger and Zane are at the village where the dead priest is, they see his hut. They move around the hut's door in a police/swat style way, to make a surpise attack on whoever might be inside. But when we cut to an inside shot of the hut, you can see there are spaces in the bambo/stick walls. Even if there was a person inside, they would easily have seen them moving around outside.
Continuity mistake: When the helicopter lands in the LZ to pick them up at the end of the movie, its position and anti-collision lights are on. Not a smart idea, for a night extraction when guys with guns are looking to shoot at you. In the next scene, the helicopter flies away and all the lights are off.
Factual error: In the beginning and during a few other parts of the movie, Tom is called "Gunny." His actual rank as shown by his insignia is Master Gunnery Sergeant. No Marine would allow someone to mis-rank him that way.
Continuity mistake: When Billy Zane is in the helicopter, he sights the sniper in his scope, the sniper being the one that just shot the chopper up. You see from the scope's view that the chopper is apparently following him running down the mountain. But, the helicopter was hovering, it wasn't following him.
Answer: According to an old post on the Bladeforums website, it was an 8" Al Mar Shadow.